Do Alt-Az GoTo mounts require constant realignment?

[Forge]

I've got a Skywatcher 12" GoTo recently and after a month or so of use I've found a minor issue. Before each viewing session I collimate and align it and for a good hour, the GoTo function (i.e. selecting an object and the telescope slewing to it) is almost pinpoint accurate. However after that using the same function, I have to manually use the controller to adjust it by quite a few degrees to get the selected object into the center of the eyepiece.

Is that expected behavior due to the nature of alt-az mounts or does it indicate a problem with the motors or encoders in my specific mount?

Just read the manual and it seems I could use the PAE function to try and correct this, but I've not tried it yet.

Thanks

[gaseous]

I think you're doing well if you're getting an hour of pinpoint accuracy! I find they can tend to lose a little accuracy over time, and tend to realign after a few hours if the target object is not within a low-power field of view, but if it's out by several degrees, then something may be amiss.

[Hemi]

The pointing accuracy of goto’s is reduced (I’ve read), with the SW encoders on. I presume that error compounds with time. You could try and see what happens with the encoders off.... I rarely manually locate if I’ve aligned so leave the encoders off mostly.

Cheers

Hemi

[Allan_L]

something I posted in another thread:


The accuracy is always best in the quadrant where your alignment stars are.
I also found the accuracy decreased as the night got colder.
That other thread also had some hints on picking quality alignment stars, just in case you missed it.

[Forge]

Thank you all, seems like the scope is doing alright. But I will try your suggestions to do some further testing